Detect clock skew during suspend From: "Rafael J. Wysocki" Detect the situations in which the time after a resume from disk would be earlier than the time before the suspend and prevent them from happening on x86_64. Signed-off-by: Rafael J. Wysocki Signed-off-by: Andi Kleen --- arch/x86_64/kernel/time.c | 10 +++++++++- 1 files changed, 9 insertions(+), 1 deletion(-) Index: linux/arch/x86_64/kernel/time.c =================================================================== --- linux.orig/arch/x86_64/kernel/time.c +++ linux/arch/x86_64/kernel/time.c @@ -1041,8 +1041,16 @@ static int timer_resume(struct sys_devic unsigned long flags; unsigned long sec; unsigned long ctime = get_cmos_time(); - unsigned long sleep_length = (ctime - sleep_start) * HZ; + long sleep_length = (ctime - sleep_start) * HZ; + if (sleep_length < 0) { + printk(KERN_WARNING "Time skew detected in timer resume!\n"); + /* The time after the resume must not be earlier than the time + * before the suspend or some nasty things will happen + */ + sleep_length = 0; + ctime = sleep_start; + } if (vxtime.hpet_address) hpet_reenable(); else